Terbium 161 PSMA in Lutetium-177 PSMA Naive Patients (TeLuNa)

March 9, 2026 updated by: Cigdem Soydal, Ankara University

Phase 2 Study of Terbium 161 PSMA in Lutetium-177 PSMA Naive mCRPC Patients

In this study it is aimed to analyze the efficacy and safety of Tb-161 PSMA I&T in the 7.4 GBq activity in a large patient group of Lu-177 PSMA naïve mCRPC patients. 3 cycles of Tb-161 PSMA will be administered with 6 weeks periods. After each cycle a triple bed quantitative single photon emission CT (SPECT)-CT scan from vertex to thigh will be acquired 24 h after every treatment of Tb-161 PSMA. In the first cycle additional time points SPECT-CT acquisitions will be obtained for dosimetric calculations. Details of dosimetry acquisitions will be provided by dosimetry partner. Routine safety blood tests including full blood counts, liver function test, electrolytes, serum PSA, and assessment for adverse events were performed every 3 weeks during study treatment. Once the patient completed three cycles of Tb-161 PSMA, they will continue to undergo clinical review, assessment for adverse events, routine safety bloods, and PSA every 6 weeks for 48 weeks. OR to treatment will be assessed by Ga-68 PSMA PET/CT using RECIP 1.0 criteria.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Radionuclide treatment with Lutetium-177 (Lu-177)-labelled prostate-specific membrane antigen (PSMA) has become a standard care of treatment for patients with metastatic castration-resistant prostate cancer (mCRPC). Main advantages of Lu-177 PSMA improvement of overall survival and quality of life. Progression of disease occurs most of the patients after Lu-177 PSMA treatment. For this reason, labelling of PSMA with other radionuclides such as alfa or Auger electrons emitters have been a subject of interest. The major advantage of Terbium-161 is, besides the beta-radiation similar to Lu-177, its additional emission of Auger electron. Additional energy arising from Auger electrons has a shorter distance. Thus, higher concentration of radiation affects micrometastatic deposits of prostatic cancer due to cause of double-strand DNA damage. Preclinical studies demonstrated superior anti-tumor activity of Tb-161 PSMA compared with the Lu-177 PSMA. Furthermore, safety of Tb-161 I&T has been documented recently with VIOLET trial as the first in human study.

In this study it is aimed to analyze the efficacy and safety of Tb-161 PSMA I&T in the 7.4 GBq activity in a large patient group of Lu-177 PSMA naïve mCRPC patients.

3 cycles of Tb-161 PSMA will be administered with 6 weeks periods. After each cycle a triple bed quantitative single photon emission CT (SPECT)-CT scan from vertex to thigh will be acquired 24 h after every treatment of Tb-161 PSMA. In the first cycle additional time points SPECT-CT acquisitions will be obtained for dosimetric calculations. Details of dosimetry acquisitions will be provided by dosimetry partner.

Routine safety blood tests including full blood counts, liver function test, electrolytes, serum PSA, and assessment for adverse events were performed every 3 weeks during study treatment. Once the patient completed three cycles of Tb-161 PSMA, they will continue to undergo clinical review, assessment for adverse events, routine safety bloods, and PSA every 6 weeks for 48 weeks.

Ga-68-PSMA and F-18-FDG PET-CT will be repeated at 8 weeks after last cycle. During cycles if any progression is observed in posttreatment SPECT/CT imaging or PSA levels, additional Ga-68-PSMA and F-18-FDG PET-CT scans will be performed. If disease progression is confirmed, then treatment will be ceased.

Patient-reported outcomes will be assessed within 3 days before cycle 1 day 1, then at 6, 12, 24, 36, and 48 weeks, using the Brief Pain Inventory-Short Form for pain, the Functional Assessment of Cancer Therapy for Prostate Cancer questionnaire for quality of life, and the Functional Assessment of Cancer Therapy-Radionuclide Therapy questionnaire for treatment-specific symptoms.

PSMA-I&T will be radiolabeled with no-carrier-added Tb-161 in the onsite hospital radiopharmacy. Labelling procedure will be provided by Thertera. After labelling quality control tests for radionuclidic purity, radiochemical purity, and radiochemical identity using high-pressure liquid chromatography and radio-thin-layer chromatography, as well as endotoxin and sterility testing will be performed. 7.4 GBq Tb-161 PSMA-I&T will be administered by slow intravenous injection in an ambulatory treatment. A minimum of 500 mL of normal saline hydration over 1-2 h will be given with radiopharmaceutical therapy, unless fluids are contraindicated. All patients will receive androgen deprivation therapy continuously throughout the trial. The subsequent activities of Tb-161 PSMA-I&T will be reduced by 20% for patients who have the following toxicities from the preceding cycle: dry mouth (grade 2), dry eyes (grade 2), nadir platelet count of less than 100 × 109/L, nadir neutrophil count of less than 1.0 × 109/L, or other significant dose-related toxicities (grade 3 or worse) that are considered both attributable to Tb-PSMA-I&T and are radioactivity-related. OR to treatment will be assessed by Ga-68 PSMA PET/CT using RECIP 1.0 criteria.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Turkey (Türkiye)
      • Ankara, Turkey (Türkiye)
        • Bilkent City Hospital
        • Contact:
        • Principal Investigator:
          • Elif Ozdemir, Prof
      • Ankara, Turkey (Türkiye), 06590
        • Ankara University Medical School Dept of Nuclear Medicine
        • Contact:
        • Principal Investigator:
          • Cigdem Soydal, Prof
        • Sub-Investigator:
          • Mine Araz, Asc Prof
        • Sub-Investigator:
          • Nuriye Ozlem Kucuk, Prof
        • Sub-Investigator:
          • Yuksel Urun, Prof
      • Istanbul, Turkey (Türkiye)
        • Memorial Sisli Hospital
        • Contact:
        • Principal Investigator:
          • Cuneyt Turkmen, Prof
      • Istanbul, Turkey (Türkiye)
        • Anadolu Sağlık Merkezi
        • Contact:
        • Sub-Investigator:
          • Kezban Berberoğlu

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Men aged 18 years or older with mCRPC (histologically or cytologically confirmed adenocarcinoma of the prostate)
  • Progressive disease as defined by the Prostate Cancer Clinical Trials Working Group 3 (PCWG3) under previous treatment with taxane chemotherapy (unless medically unsuitable) and at least one second-generation androgen receptor pathway inhibitor (ARPI)
  • Adequate bone marrow, hepatic, and renal function
  • Eastern Cooperative Oncology Group performance status of 0-2;
  • A life expectancy of at least 6 months.
  • On Ga-68 PSMA PET/CT, a maximum standardised uptake value (SUVmax) of at least 20 in at least one metastasis and SUVmax of at least 10 in measurable soft tissue metastases.
  • Patient has provided written informed consent
  • PSA progression: minimum of 2 rising PSA values from baseline measurement with interval of ≥1 wk between each measurement
  • Soft-tissue progression: per RECIST 1.1
  • Bone progression: ≥2 new lesions on bone scan
  • At least 3 wk interval since completion of surgery or radiotherapy before registration

Exclusion Criteria:

  • Patients with discordant metastases defined as positive on 2-[¹⁸F]fluoro-2-deoxy-D-glucose (FDG) PET-CT with minimal uptake on Ga-68-PSMA PET-CT
  • Previous treatment with another radioisotope
  • Other malignancies within the previous 2 years before registration other than basal cell or squamous cell carcinomas of skin or other cancers that are unlikely to recur within 24 months
  • Concurrent illnesses that could jeopardise the ability of the patient to undergo the trial procedures.
  • Patient has symptomatic brain metastases or leptomeningeal metastases
  • Patient has symptomatic or impending cord compression unless appropriately treated beforehand and clinically stable for >4 wk

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Tb-161 PSMA treatment arm
Patients who will treat with 3 cycles of Tb-161 PSMA with 7.4 GBq activity
Drug: Terbium 161- PSMA I&T
cycles of Tb-161 PSMA I&T with 7.4 GBq activity

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Objective response evaluation
Time Frame: up to 6 weeks after last cycle of treatment (each cycle is 1 day)
Response to treatment will be assessed by Ga-68 PSMA PET/CT using RECIP 1.0 criteria.
up to 6 weeks after last cycle of treatment (each cycle is 1 day)
PSA response evaluation
Time Frame: within three weeks after each treatment cycle and with 6 weeks periods from 6 to 48 weeks after last cycle (each cycle is 1 day)
At least 50% change in the serum PSA levels
within three weeks after each treatment cycle and with 6 weeks periods from 6 to 48 weeks after last cycle (each cycle is 1 day)
Change in QoL
Time Frame: within 1 months after each cycles (each cycle is 1 day)
Change in QoL will be evaluated by change in scores of the Functional Assessment of Cancer Therapy for Prostate (FACTP) questionnaire for treatment-specific symptoms.
within 1 months after each cycles (each cycle is 1 day)
Toxicity Evaluation
Time Frame: within three weeks after each treatment and with 6 weeks period within 6 to 48 weeks after last cycle (each cycle is 1 day)
To analyze the organ toxicities of Tb-161 PSMA treatment with 7.4 GBq activity in 3 cycles with Common Terminology Criteria for Adverse Events (CTCAE) scores
within three weeks after each treatment and with 6 weeks period within 6 to 48 weeks after last cycle (each cycle is 1 day)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Tumor absorbed dose calculations
Time Frame: within 96 hours after first cycle (each cycle is 1 day)
To calculate the mean tumor absorbed doses in Gy with multi-frame SPECT/CT images with multi compartment model
within 96 hours after first cycle (each cycle is 1 day)
Organ absorbed dose calculations
Time Frame: within 96 hours after first cycle (each cycle is 1 day)
To calculate the mean organ absorbed doses for salivary glands, kidney, liver and bone marrow in Gy with multi-frame SPECT/CT images
within 96 hours after first cycle (each cycle is 1 day)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ankara University

Collaborators

Oncosia Scientific GmbH
EDH Nukleer Tip ve Saglik Hizmetleri Ltd. Sti.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 1, 2026

Primary Completion (Estimated)

August 1, 2028

Study Completion (Estimated)

September 1, 2028

Study Registration Dates

First Submitted

February 18, 2026

First Submitted That Met QC Criteria

February 24, 2026

First Posted (Actual)

March 2, 2026

Study Record Updates

Last Update Posted (Actual)

March 11, 2026

Last Update Submitted That Met QC Criteria

March 9, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • TeLuNa Trail

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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